Communication system network that includes a method for maintaining a system data database

ABSTRACT

In a communication system network that includes a processing multiplexer and a plurality of communication systems, wherein each of the communication systems includes a plurality of signal sources, a plurality of signal destinations, and a processing interface means and wherein the processing multiplexer includes system data database means that stores information pertaining to communication system configuration data, a method for maintaining the system data database is described. Maintaining the system data database means comprises querying the processing multiplexer interface means of at least one communication system for information pertaining to communication system configuration data. Upon receiving the information, allocating entries in the system data database means for the information pertaining to communication system configuration data and entering the information into the allocated entries.

This patent application is a continuation-in-part of Ser. No. 509,915,filed Apr. 16, 1990, now U.S. Pat. No. 5,175,727, entitled ACOMMUNICATION SYSTEM NETWORK.

TECHNICAL FIELD

This invention relates generally to communication systems and inparticular to a method and apparatus that allow such communicationsystems to be linked together to create a communication system network.

BACKGROUND OF THE INVENTION

Presently, there are two basic types of land-mobile communicationsystems: conventional communication systems (FIG. 1) and trunkedcommunication systems (FIG. 2). Each type of communication systemcomprises a plurality of communication units, a limited number ofcommunication resources, a communication resource allocator, and aplurality of operator stations (consoles). The communication resourceallocator comprises a plurality of base interface modules (BIMs), aplurality of operator mux interface modules (OMIs), a plurality of audioexpansion interface modules (AEIs), and at least one TDM bus. Each BIMacts as both a signal source and a signal destination. As a signalsource, the BIM receives audio signals from at least some of theplurality of communication units, via a repeater or base station,converts the signals into digitized signals, and sources them to a slotin the TDM bus. See FIG. 3 for a typical TDM slot assignment pattern.(For an operational description of the TDM bus and slot location, referto Motorola, Inc., Pub. No. R4-2-37C, CENTRACOM Series II ControlCenters (March, 1988).) The BIM also acts as a designated signal sourceby conveying communication system data produced by a communication unit,or units, to the rest of the communication system. As a signaldestination, the BIM receives digitized signals from the TDM bus,converts them to audio signals, and sends the audio signals to therepeater or base station such that the audio signals may be transmitted,via a communication resource, to at least some of the plurality ofcommunication units.

Within either type of communication system, an OMI and an AEI are usedto interface a console to the rest of the system. Generally, the OMIcontains, in firmware, information that allows its respective console toperform supervisory functions and information regarding the typicalcommunication system configuration. The typical communication systemconfiguration includes, but is not limited to, the number of repeaters,number of signal sources, the number of signal destinations, the TDMslot assignments for each signal source and signal destination, the typeof each BIM, and number and codes of communication groups. (For adetailed description of supervisory functions and CCMs, refer toMotorola, Inc. Pub. No. R4-2-73, CENTRACOM Series II Plus ControlCenters (April, 1988). However, for use herein, consoles need notincorporate all of the described features as listed in the CENTRACOMSeries II Plus Control Centers publication.) The OMI, as a designatedsignal source, sources communication system data to the TDM bus, whereinthe communication system data comprises information about the typicalcommunication system configuration, information about selectedsupervisory functions, and/or information about selected signaldestinations. The OMI further acts as a signal source by receiving audiosignals from its respective console, converting the signals intodigitized signals, and sourcing the digitized signals, in theappropriate slot, to the TDM bus.

The OMI, however, does not act as a signal destination for itsrespective console, the AEI performs this function. The AEI, as a signaldestination, receives digitized signals from the TDM bus, converts thesignals into audio signals, and sends the audio signals to a speakerthat is controlled by an assigned CCM of the console. The audio signalssent to the speaker may comprise a plurality of audio signals that weregenerated by several signal sources, such that the operator of theconsole may monitor and supervise several signal source via one speakerand one CCM per signal source. The AEI acts as a signal destination foreach CCM on a console, thus if a console has ten CCMs, the AEI acts asten signal destinations. It should be noted that the actual signalsources and signal destinations are the communication units and console,however, they are addressed by their respective communication systeminterfacing modules (BIMs, OMIs, and AEIs). Thus, for the purposes thisdiscussion, the OMIs and BIMs will be referenced as signals sources,while the AEIs and BIMs will be referenced as signal destinations.

As described above, conventional communication systems and trunkedcommunication systems have several characteristics alike, however, eachcommunication system operates in a distinct mode. The typicalconventional system of FIG. 1 comprises a plurality of communicationunits, a plurality of repeaters that transceive information viacommunication resources, a communication resource allocator (centralelectronics bank (CEB)), and a plurality of consoles. Also shown is acomputer aided dispatcher (CAD) which may also be incorporated intotrunked communication system. (For a description of the CAD, refer toMotorola, Inc. Pub. No. R4-2-73, CENTRACOM Series II Plus ControlCenters (April, 1988).) The typical communication system configurationof a conventional communication system has communication groups assignedto specific repeaters, wherein specific consoles are assigned to monitorsome of the communication groups. (A communication group comprises atleast some of the plurality of communication units that are typicallyused for like purposes, e.g. police department, fire department, etc.)The repeater and communication group assignments may be changed by aCAD, but regardless of the assignments, a console monitors only therepeaters having at least one of its communication group assigned to it.For a further discussion of the convention system refer to U.S. Pat. No.4,630,263, entitled TIME DIVISION MULTIPLEX COMMUNICATION CONTROLSYSTEM, assigned to Motorola, Inc.

The typical trunked communication system of FIG. 2 comprises a pluralityof communication units, a plurality of repeaters that transceive signalsvia communication resources, a communication resource allocator, and aplurality of consoles. (As with a conventional communication system, thecommunication resources may be telephone lines, frequency pairs, carrierfrequency, or TDM slots.) The typical communication system configurationof the trunked communication system comprises the communication unitsarranged into a plurality of communication groups, where the repeatersare allocated to a communication group upon request. The consoles areassigned to monitor specific communication groups, however, the consolecannot monitor a specific repeater as in a conventional communicationsystem. The console must receive information from the communicationresource allocator about the repeater that has been allocated to one ofits communication groups. For a further description of the trunkedcommunication system refer to U.S. Pat. No. 4,698,805 entitled CONSOLEINTERFACE FOR A TRUNKED RADIO SYSTEM, assigned to Motorola, Inc.

Despite all the features that each communication system offers tosubscribers (user of a communication unit) and console operators, theiruse is limited to the communication system that the subscribers andconsole operators are affiliated with. This may be a substantiallimiting factor in large metropolitan areas having a large number ofsubscribers and console operators. For example, if a city has a largepolice force, fire department, and other civil service departments,several communication systems may be needed to adequately service them.Because communication systems may not actively communicate with othercommunication units, the city must have several central control stationsinstead of one. For example, if the city has thirty communicationsystems with the police force subscribing to several of the systems, thecity's police force may not all communicate together, nor can oneconsole operator send a supervisory message to the entire police force.Therefore, a need exists for a communication system network that allowscommunication units in either type of communication system tocommunicate with other communication units in the same or differentcommunication systems and that allows console operators to monitor andsupervise communication groups in its communication system as well ascommunication groups in other communication systems.

SUMMARY OF THE INVENTION

These needs and others are substantially met by the communication systemnetwork that includes a method for maintaining a system data database.The communication system network includes a processing multiplexer and aplurality of communication systems, wherein each of the communicationsystems includes a plurality of signal sources, a plurality of signaldestinations, and a processing interface means and wherein theprocessing multiplexer includes system data database means that storesinformation pertaining to communication system configuration data.Maintaining the system data database means comprises querying theprocessing multiplexer interface means of at least one communicationsystem for information pertaining to communication system configurationdata. Upon receiving the information, allocating entries in the systemdata database means for the information pertaining to communicationsystem configuration data and entering the information into theallocated entries.

In an aspect of the present invention, maintaining the system datadatabase means further comprises updating the information with newinformation whenever it changes with respect to a signal destination ofthe at least one communication system.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a typical conventional communication system of theprior art.

FIG. 2 illustrates a typical trunked communication system of the priorart.

FIG. 3 illustrates a diagram of a TDM bus of the prior art.

FIG. 4 illustrates a communication system network in accordance with thepresent invention.

FIGS. 5A, 5B, and 5C illustrates a TDM slot arrangement of the sourceinterface bus and the destination interface buses.

FIG. 6 illustrates a circuit diagram of an ambassador board.

FIG. 7 illustrates a circuit diagram of an ambassador interfacemultiplex interface board.

FIG. 8 illustrates a logic diagram of a process for producing addressesfor the destination database.

FIG. 9 illustrates a logic diagram of a process for producing addressesfor the signal database.

FIG. 10 illustrates a portion of the destination database having exampledata stored therein.

FIG. 11 illustrates a portion of the signal database having example datastored therein.

FIG. 12 illustrates a logic diagram of a process for updating eachcommunication system's communication system configuration database.

FIG. 13 illustrates a logic diagram of a process for controlling accessto the AEB data bus.

BEST MODE FOR CARRYING OUT THE INVENTION

FIG. 4 illustrates a communication system network that comprises aplurality of communication systems (401) and a processing multiplexer orambassador electronics bank (AEB) (402). The plurality of communicationsystems (401 may comprise conventional communication systems (100)and/or trunked communication systems (200). The AFB (402) comprises aplurality of ambassador boards (403), a system synchronization circuit(404), an AEB data bus (405), an AEB signal buses (406), and a pluralityof communication ports (407). Each of the ambassador boards (403)comprises a receiving decoder (408), a detection circuit (409),communication system database circuitry (410), an address circuit (411),a processing circuit (412), a sending circuit (413), signal databasecircuitry (414), an address bus (415), and a plurality ofinterconnection buses (416). Each of the plurality of communicationsystems (401) is coupled to a communication port by at least one sourceinterface bus (426) and at least one destination interface bus (427).Each communication system (401) comprises an ambassador interface muxinterface module (AIMI) (417), a plurality of signal sources (418), aplurality of signal destinations (419), a data bus (420) a source bus(421), and a destination bus (422). The AIMI (417) comprises a sendingcircuit (423), a receiving circuit (424), and a processing circuit(425).

Generally, within the AEB (402), each ambassador board (403) is operablycoupled to at least one communication port (407), to the AEB data bus(405), and to the AEB signal buses (406). The best mode contemplated haseach ambassador board (403) coupled to two communication ports (407),such that each ambassador board may service two communication systems(401). To achieve this, the ambassador board (403) would include asecond receiving decoder (not shown) and a second sending encoder (notshown) connected to another communication port (407). Internally, thesecond receiving decoder and the second sending encoder are connected tothe signal database circuitry (414), the detection circuit (409), thesystem data database circuitry (410), and the addressing circuit (411)in a similar fashion as the first sending encoder (413) and firstreceiving decoder (408). Because the second receiving decoder and thesecond sending encoder operate in a similar fashion as the firstreceiving decoder (408) and the first sending encoder (413),respectively, only the operation of the first receiving decoder (408)and the first sending encoder (413) will be discussed.

Upon receiving signals and communication system data from acommunication system, via a source interface bus (426), the receivingdecoder decodes the signals and communication system data and separatesthem. (A more detailed description of the receiving decoder's operationand the format of the source interface bus will be discussed below.) Theseparated signals are placed on one of the AEB signal buses (406) andthe separated communication system data is routed to the system datadatabase circuitry (410). The AEB signal buses (406) comprisesthirty-two individual buses, each bus being dedicated to a communicationsystem, such that the separated signals are placed on the bus dedicatedto the communication system that produced the signals. The dedication ofAEB buses (406) to communication systems (401) is determined by whichcommunication port the communication system is operably coupled to.Thus, the communication system (401) that is coupled to the firstcommunication port (407) has the first AEB bus dedicated to it.

The separated signals produced by each of the communication systems(401), are synchronously placed on their respective AEB signal bus(406). (A detailed description of the communication system networksynchronization process will be discussed below). Each signal databasecircuitry (414) is coupled to all the AEB signal buses (406) and, forthis portion of the synchronization period or predetermined time frame,stores each of the separated signals in a signal database as an eightbit PCM code. The best mode contemplates that each signal database willbe a dual port random access memory device (DPRAM), nevertheless, anyreprogrammable memory device will suffice. The signal database may storeeach of the signals as information pertaining to them, if a differentcoding scheme of the signals is employed, such as a linearrepresentation or other digital representation. (A detailed descriptionof the signal database circuitry (414) will be discussed below.)

The separated communication system data is routed to the system datadatabase circuitry (410). The separated communication data generallycomprises information about the typical communication systemconfiguration (i.e. communication group-console assignments, number ofrepeaters, number of consoles, composition of communication groups inthe communication system), information about requested, or selected,supervisory functions, and information about signal destinations. Theinformation about signal destination is stored, during a portion of thesynchronization period or predetermined time frame, as an eight bit PCMcode in a destination database. The best mode contemplates that eachdestination database will be DPRAM, nevertheless, any reprogrammablememory device will suffice. The remaining separated communication systemdata is stored in random access memory devices (RAM), or reprogrammablememory device. The communication system data that is stored in RAM issubsequently placed on the AEB data bus (405). (A detailed descriptionof the system data database circuitry (410) will be discussed below.)

The addressing circuit (411) produces addresses for the separatedsignals and for the separated communication system data. The addressesare used by the signal database circuitry (414) and the system datadatabase circuitry (410) to store the respective information inidentifiable locations. The address for each signal is determined by thecommunication system that is from and the signal source that generatedit. For example, if the signal was generated by the third signal sourceof the fifteenth communication system its address may be 01111 00011.Similarly, the address for the communication system data is determinedby the communication system it is from and the designated signal sourcethat produced it.

Once the signals or information pertaining to the signals are stored ineach of the signal databases and the communication system data or theinformation pertaining to the communication system data is stored in therespective system data database circuit within a portion of thepredetermined time frame, in the next portion of the predetermined timeframe, the processing circuit (412) in each ambassador board (403)processes the stored signals based on, at least in part, on the storedcommunication system data. The processing of the stored signalstypically involves producing processed signals for each of the signaldestinations of the communication system coupled to the ambassador board(403). The processed signals typically comprise a summation of signalsthat the signal destination is to receive, wherein the volume levels ofeach of the summed signals may be varied. (A detailed description of theprocessing circuit will be discussed below.)

In a subsequent portion of the predetermined time frame orsynchronization period, the processed signals are routed to the sendingencoder (413) of the ambassador board (403). The sending encoder (413)encodes the processed signals and data produced by the system datadatabase circuitry (410). Once the information is encoded, it is placedonto the destination interface bus (427). The best mode contemplatesthat the destination interface bus (427) will comprise two buses, suchthat each communication system may have twice as many signaldestinations as signal sources.

The master synchronization circuit (404) of the AEB (402) generates, atleast, a master clock signal and a frame sync signal. The best modecontemplates that the master clock signal will have a frequency of about2.048 MHz and the frame sync signal will have a frequency of about 8KHz. Each communication system receives the master clock signal and theframe sync signal from the master synchronization circuit (404) andreconstructs it to produce its own clock signal of about 2.048 MHz andown frame sync signal of about 8 KHz. Synchronization buffers are usedto compensate for propagation delays between the communication systemsand the AEB, operation of the synchronization buffers will be discussedbelow. Due to the propagation delays between the communication systemsand the AEB, it several frame sync signals (predetermined time frame) totransmit a signal from a signal source to a signal destination. The bestmode contemplates that the predetermined time frame will comprises abouteleven frame sync signals, two for producing and placing signals on thesource interface bus, two for receiving and placing the signals on theAEB signal buses (406), two for storing the signals in the signaldatabase, one for processing the signals, two for placing the processedsignals on the destination interface buses (427), and two for routingthe processed signals to the respective signal destinations.

Generally, within each communication system (401), the AIMI (417) isoperably coupled to the plurality of signal sources (418) and theplurality of signal destinations (419) via a CEB TDM data bus (420), aCEB TDM source bus (421) and two CEB TDM destination buses (422) (onlyone shown). As mentioned, the plurality of signal sources (OMIs and/orBIMs) receive audio signals generated by either a communication unit ora console and convert the signals into digitized audio. The digitizedaudio is placed on the CEB TDM source bus (421) in the slot assigned tothe particular OMI or BIM. (See FIG. 3 for a graphic representation ofslot assignments.) At least some of the OMIs and or BIMs, as designatedsignal sources, generate communication system data and place it on theCEB TDM data bus (421). (Access to the CEB TDM data bus is generallybased on a round robin polling process, such that only one BIM or oneOMI is designated to transmit data on the CEB TDM data bus at any giventime.)

The sending circuit (423) of the AIMI (417) receives the digitized audiofrom the CEB TDM source bus (421) and the communication system data fromthe CEB TDM data bus (420) per frame. The sending circuit (423) placesthe digitized audio and the communication system data on the sourceinterface bus (426). After the AEB processes the digitized audio and thecommunication system data, the processed signals are received by thereceiving circuit (425). The receiving circuit (425), via the CEB TDMdestination bus (422), routes the processed signals to the plurality ofsignal destinations (419).

FIG. 5 illustrates a TDM format of the source interface bus (500) andthe destination interface buses (501 and 502). The TDM format of thesource interface bus (500) comprises a train of frames, each frameconsisting of thirty-two slots. The first slot contains sync signalinformation that comprises a frame header code to indicate the beginningof a frame. The next thirty slots comprise an eight bit PCM coderepresenting signals produced by the signal sources of the communicationsystem. The last slot of the frame comprises an eight bit PCM coderepresenting communication system data. The TDM format of the firstdestination interface bus (501) comprises a train of frames, whereineach frame consists of thirty-two slots. The first slot contains a frameheader code, the next thirty slots contain an eight bit PCM coderepresenting processed signals for some of the signal destinations, andthe last slot contains network data that may be for any of the signalsources and/or signal destinations. The TDM format of the seconddestination interface bus (502) comprises a train of frames, whereineach frame comprises thirty-two slots. The first slot comprises a frameheader code, while the remaining slots contain eight bit PCM codesrepresenting the processed signals for the remaining signaldestinations. The frame header code is an eight bit signal that is usedto synchronize the communication system to the AEB (402). The best modecontemplates that the frame header code will be the binaryrepresentation of the number eight. It should be apparent to apractioner skilled in the art that the assignment of slot locationswithin a frame may be varied from the above description withoutsubstantially altering the spirit of the present invention.

FIG. 6 illustrates a block diagram of an ambassador board (403) that, aspreviously mentioned, comprises a receiving decoder (408), a detectioncircuit (409), communication system database circuitry (410), an addresscircuit (411), a processing circuit (412), a sending encoder (413), andsignal database circuitry (413). The receiving decoder (408) receivesand decodes signals and communication system data received on the sourceinterface bus (426). The signals, the sync signals, and thecommunication system data are received through the receiver, or buffer,(601) and sent to a frame decoder (602). The best mode contemplates thatthe frame decoder (602) will be a Manchester decoder such that the syncsignals, the signals, and the communication system data may be decoded,or separated. The separated communication system data is routed to adata extractor (603), while the separated signals are routed to anelastic store device (604). Both the data extractor (603) and theelastic store device (604) utilize the separated sync signal.

The data extractor (603) which may be a field programmable gate array,extracts the communication system data contained in the last slot of theframe as stores it. (Recall from FIG. 3 that only portions of data aretransmitted in any one frame.) The data extractor (603) continuallyextracts the communication system data from the last slot and stores ituntil a complete communication system data message has been stored. Oncea complete data message is contained with the data extractor (603), thedata extractor (603) routes the complete message to the system datadatabase circuitry (410). A detailed description of the system datadatabase circuitry (410) will be discussed below.

The elastic store device (604), which may be a DPRAM, is used as asynchronization buffer and comprises two identical sections. Thesections are used in an alternative manner, such that when one sectionis storing signals, the other section is sourcing signals to one of theAEB signal buses (406). When a frame cycle ends, the sections reverseroles, such that the section that was storing signals in the previousframe cycle is now sourcing the signals to one of the AEB signal buses(406), while the other section is storing signals from the frame decoder(602). Thus, it takes two frame cycles, or signals, to receive and placesignals on the AEB signal buses (406). If the sync signal in acommunication system is slightly different than the sync signal producedby the AEB, the elastic store device (604) will separate the sourcingand storing of signals by one frame cycle when the source pointer andstore pointer are at the same location in a section.

The addressing circuit (414) of the ambassador board (403) comprises adestination address generator (618) and a signal address generator(619). The destination address generator (618) typically comprises amicroprocessor, or other digital processor, that performs the logicfunctions as shown in FIG. 8. To establish addresses for each of thesignal destinations of the respective communication system, theambassador board (403) queries the AIMI, or processing multiplexerinterface means, (417) of the respective communication system regardingthe communication system configuration (800). (Generally, while theambassador board, or communication system interface means, is in thequery mode, it cannot source digital audio signals to the AEB signalbuses.) As previously mentioned, the communication system configurationcomprises information about the number of signal sources and signaldestinations that are contained in the communication system. Afterreceiving the communication system configuration (800), the ambassadorboard (403) queries the AIMI (417) regarding the number of entries, oraddresses, the communication system is going to need in the destinationdatabase (801). The number of entries is based on the number of digitalaudio signals that will be summed together for each signal destination.For example, if the communication system has fifty signal destinationsand each signal destination is to have four digital audio signals summedtogether, the number of entries needed would be two hundred. Also thesome entries would be needed for active data transmissions.

After querying the AIMI and receiving the requested information, theambassador board enters the received information into the allocatedentries of the destination database for each of the signal destinations.Once the information is entered, the ambassador board verifies that theinformation stored is the information that was received. If theinformation stored matches the information received, the ambassadorboard enters an inactive mode which signals the communication systemthat it is ready to source digital audio signals to the AEB signalbuses. The communication system may activate, via an OMI, the ambassadorboard by transmitting an activation data packet to the ambassador board.

If a communication system (401) is connected to more than one ambassadorboard (403) (802), each of the ambassador boards that the AIMI, orAIMIs, (417) are connected to verifies that they each have received andstored the same information in steps 800 and 801 (803). (Verification ofthe information stored may be done by a CRC redundancy check or similarmethod.) The best mode contemplates that each communication system willbe redundantly connected to the AEB via two ambassador boards. Oneambassador board will be designated as an active board, while the otherwill be designated as a backup board. This information will be stored ina communication system network database contained in each of theambassador boards (not shown). With each ambassador board having acommunication system network database, the ambassador board will knownwhen the active board becomes inactive and when the backup board becomesactive such that the ambassador boards will know which AEB signal bus toreceve digital audio signals from. The communication system networkdatabase may also contain the ambassador to AEB signal bus data andambassador to communication port data.

If the ambassador boards do not agree on the information received andstored because the CRC redundancy check values are different (803), theyquery the AIMI again. The ambassador boards may not agree on theinformation because each ambassador board received the information fromits respective AIMI, wherein the AIMIs of the communication system haddifferent communication system configuration data, The requeryingprocess will repeat until the ambassador boards agree on theinformation, or until one ambassador board assumes priority. (Therequerying process may query the OMIs of the communication system toobtain the system configuration data as opposed to, or in addition, toquerying the AIMIs.) An ambassador board may assume priority either bydesignation or by a quality test. For designated priority, theinformation acquired by the active board is given priority after severalunsuccessful attempts to match the information. For priority based on aquality test, the ambassador board having a higher quality connection tothe AIMI will be given priority, where a higher quality connection may,at least in part, be defined as lower transmission errors between theAIMI and the ambassador board.

If the communication system is connected to only one ambassador board,or the ambassador boards are in agreement on the information supplied insteps 800 and 801, the active ambassador board assigns TDM slotlocations in the destination interface buses to each of the signaldestinations of the communication system (804). After the TDM slotlocations are assigned (804), the ambassador board receives from eachOMI, as a designated signal source, destination information for each ofthe signal destinations that the OMI is affiliated with (805). If thecommunication system configuration has not changed (806), thedestination address generator (618) awaits a change. If thecommunication system configuration has changed (806), the destinationaddress generator (618) repeats the process at step 801. Note that ifthe backup ambassador board becomes the active board, the destinationsignal generator (618) detects this and sources the backup boardinformation as the destination addresses, without substantialinterruption.

The signal address generator (619) of the ambassador board (403)generates addresses for the signal database (616). The signal addressgenerator (619) which may be a microprocessor, or any digital processingdevice, generates the addresses as illustrated in the logic diagram ofFIG. 9. A step 900, the signal address generator (619) records theambassador board to AEB signal bus relationship. The best modecontemplates that the AEB will have thirty-two AEB signals buses and andthe equivalent of a card cage having thirty-two card connectors. Thecard connectors are affiliated with an AEB signal bus based on theirphysical location. For example, the first card connector is affiliatedwith AEB signal bus 00000 and the thirty-second card connector isaffiliated with AEB signal bus 11111. Thus, the ambassador board to AEBsignal bus relationship is determined by the card connector that theambassador board is plugged into. As an alternative example, each cardconnector may be affiliated with two AEB signal buses such that thefirst card connector is affiliated with AEB signal buses 00000 and10000, while the sixteenth card connector is affiliated with AEB signalbuses 01111 and 11111.

After the ambassador board to AEB signal bus relationship is established(900), the signal address generator (619) records the ambassador boardto communication system relationship (901). The ambassador board tocommunication system relationship is established by the physicalconnection of a communication system to a communication port. The bestmode contemplates having thirty-two communication ports, each physicallyaffiliated with a card connector, such that the first communication portis affiliated with the first card connector. Thus, the ambassador boardto communication system relationship is established by plugging theambassador board into a card connector and coupling the communicationsystem to the corresponding communication port.

If a communication system is only coupled to one ambassador board (902),the signal address generator (619) maps the communication system to theAEB signal bus that the ambassador board is affiliated with (903).Specific addresses for the signal database are determined by the AEBsignal bus affiliation and the slot location in the source interface bus(426). For example, if the signal to be stored is generated in thecommunication system affiliated with the fifth AEB signal bus andoccupies the tenth slot in the source interface bus, the signal addressgenerator will produce 00101 01010 (5,10 in decimal). Thus, the signalsproduced by that signal source will be addressed as 00101 01010 untilits slot location is changed or the communication system to ambassadorboard relationship changes. If the communication system to ambassadorboard relationship changes, or the AEB signal bus to ambassador boardrelationship changes (904), the process repeats at step 900.

If a communication system is coupled to more than one ambassador board(902), an active ambassador board and a backup ambassador board aredetermined (905). (The selection of an active ambassador board and thebackup board was discussed above). Once the active and backup ambassadorboards have been established (905), the signal address generator (619)maps the communication system to the AEB signal bus that the activeambassador board is affiliated with (906). Specific addresses for thesignals are determined as described above. The specific addresses remainconstant until a change occurs in either the communication system toambassador board relationship changes (backup board becomes active), orthe ambassador board to the AEB signal bus relationship changes (907).If a change does occur (907), the process repeats at step 900.

The signal database circuitry (414) comprises a signal database (616)which may be a DPRAM and an AEB TDM receiver (617) which may be a fieldprogrammable gate array. The AEB TDM (617) is coupled to each of the AEBsignal data buses (406) and receives the signals, per frame cycle, fromeach AEB bus and routes them to the signal database (616). The signaldatabase (616) comprises two sections that operate in an alternativemanner. Like the elastic store (604), during a frame cycle, the signaldatabase (616) is storing signals received by the AEB TDM receiver (617)in one section and sourcing signals to the processing circuit (412) fromthe other section. On the next frame cycle, the sections reverse roles,the section that was storing signals is now sourcing signals and thesection that was sourcing signals is now storing signals. The signalsare stored in either section of the signal database (616) based on anaddress generated by a signal address generator (619) of the addresscircuit (411). The signal address generator (619) produces addresses forthe signals as described above.

FIG. 11 illustrates a typical format of the signal database (619). Thesignal database (619) comprises a plurality of address fields (1100), aplurality of PCM code fields (1101), a first section (1102), and asecond section (not shown). The second sections format will be identicalto the first section (1102), thus only a discussion the first sectionsformat will be presented. As mentioned above, the signal databaseaddresses are determined by AEB bus and slot location of the signalsource. Address 00000 00000 (1103) is the address for the PCM code forslot 0 of AEB bus 0. Similarly, addresses 00000 00001 (1104), 0000000010 (1105), 10111 00000 (1106), and 10111 00001 (1107) are addressesfor the PCM codes for slot 1 of AEB bus 0, slot 2 of AEB bus 0, slot 0of AEB bus 23, and slot 1 of AEB bus 23, respectively. Each of the PCMcodes is stored during one frame cycle are sourced during the subsequentframe cycle as described above. The PCM codes of the signals may beplaced at different addresses than described above, nevertheless, thebest mode contemplates the above addressing process.

The system data database circuitry (410) comprises a first X25 PCcontroller (606), a bus arbitrator (607), a microprocessor (608), arandom access memory device or devices, (609) (RAM), read only memorydevices (610) (ROM), a system data database (611), a second X25 PCcontroller (612), a data arbitrator (613), an address bus (614) and adata bus (615). The first and second X25 PC controllers are devicesmanufactured by Motorola, Inc. The ROM (610) may be fixed ROMs, EPROMsand/or EEPROMs, and the bus arbitrator (607) may be a field programmablegate array. The destination database (611) may be a DPRAM that comprisestwo sections, where the sections operate as described below withreference to FIG. 10.

The bus arbitrator (606) allocates the ambassador board data bus (615)to either the first X.25 PC controller (606), the microprocessor (608),or the second X.25 PC controller (612). Allocation of the data bus (615)is given to the section that needs it. For example, when the first X.25PC controller (606) is sourcing communication system data to thedestination database (611) and the RAM (609), the bus arbitrator (606)allocates the data bus (615) to the first X.25 PC controller (606).Similarly, when the microprocessor (608) or the second X.25 PCcontroller (612) has data to place on the data bus (615), the busarbitrator (606) allocates it to the requesting data source.

The first X25 PC controller (606), as one of its functions, receives thecommunication system data and separates it into signal destination data,system configuration data, and supervisory data. The signal destinationdata contains, for each signal destination of a communication system,information pertaining to which signals it is to receive and at whatvolume level. For example, the signal destination data may indicate thata signal destination is to only receive one signal from a signal sourcein another communication system at full volume, or the signaldestination data may indicate that a signal destination is to receivethe sum of thirty signal sources from various communication systems atvarious volume levels. The signal destination data for each signaldestination is stored in the sections of the destination database (611)based on an address generated by a destination address generator (618)of the address circuit (411). The destination address generator (618)produces addresses for the signal destination data as described above.

The system configuration data and supervisory data are stored in the RAM(609). Unlike the destination database (611) which stores data only forthe affiliated communication system(s), the RAM (609) stores data forthe entire communication system network (network data). The second X25PC controller (612) that is operating in transparent mode interfaces thedata stored in RAM (609) with the AEB data bus (405). The data arbiter(613), which may be a field programmable gate array, controls thesourcing and sinking of data to and from the AEB data bus (405) and thesecond X.25 PC controller (612). The data arbiter (613) allows thesecond X.25 PC controller (612) to sink and source network data to andfrom the AEB data bus (405).

The detection circuit (409), which may be substantially comprised in themicroprocessor (608), monitors the signal and communication system datathis is being received from the affiliated communication system. Ifsignals are not being received because the communication system is notoperably coupled to the ambassador board (403), the detection circuit(409) generates a data signal that indicates to the rest of thecommunication system network that the affiliated communication system innot actively connected to the network. The detection circuit (409) alsogenerates a mute signal that is stored in the signal database (616) atthe addresses of the signal sources of the affiliated communicationsystem.

FIG. 10 illustrates a format of the destination database (611). Thedestination database format comprises a first section (1009), and secondsection (1010), a plurality of address fields (1000), wherein, at eachaddress field, the format comprises an input control signal field (I/C)(1001), two frame control signal fields (FCI and FC2) (1002 and 1003),three volume control signal fields (VOL.1, VOL.2 and VOL.3) (1004, 1005,and 1006), a signal source bus field (1007), and a signal source slotfield (1008). As previously mentioned, the number of entries, oraddresses, for the affiliated communication system, or communicationsystems, is determined by the number of signal sources that each signaldestination is to receive signals from. Also mentioned is that eachsignal destination of the affiliated communication system is assigned aslot location in one destination interface buses (427). Thus, after aframe header, or sync, signal, the first entries into the destinationdatabase (611) are for the signal source assigned to slot 1 of the firstdestination interface bus.

If there are two communication systems affiliated with the ambassadorboard, each section (1009 and 1010) of the destination database (611)will have two entry blocks, one for each affiliated communicationsystem. The number of entries in each block is determined as describedabove, such that the total number of entries do not exceed the capacityof the destination database (611). In each entry block, the first entrywill be a frame header such that the entry blocks are in sync with thedestination interface buses of the affiliated communication systems.After both entry blocks have been entered, the remaining entries in thedestination database are filled with null information.

As an illustrative example, assume that the ambassador board isconnected to only one communication system, that the signal sourceassigned to the first slot of the first destination interface bus hasthe following destination data (1011), and that the first section (1009)is in the storing mode. Recall that the signal destination datacomprises the signal sources that the signal destination is to receivesignals from and at what volume. For this example, the first signaldestination is to receive signals from four signal sources having abus-slot addresses as shown. The volume levels for each signal is storedin the three volume control fields (1004, 1005, and 1006). By havingthree fields, a signal's volume level may be set at any one of sixteenlevels. For this example, 111 is considered maximum volume and 000 isconsidered minimum volume, however, any binary representation of minimumto maximum volumes may be used. The I/C field (1001) indicates the endof a signal destination's destination data. For this example, thatoccurs at address 000, 000, 000, 011.

As a continuation of the above example, assume that the affiliatedcommunication system has only two signal destinations and the secondsignal destination is to receive signals from two signals sources. Thevolume levels and the bus-slot address of the signals sources are shown.Once the entries for both signal destinations have been entered, theremaining entries are filled with null information information (1013 and1014). The best mode contemplates that one section of the destinationdatabase will accommodate upto 128 signal destinations and upto 1750entries. Thus, for example, each signal destination could receivesignals from about 14 signal sources. It will be apparent to apractioner skilled in the art that the destination database may be madelarger or smaller to accommodate more or less signal destinations. Italso should be apparent that a signal destination may receive signalsfrom any number of signal destinations so long as the number doesn'texceed the capacity of the destination data base.

The null information is entered into the destination database (611) bythe microprocessor (608). Recall that the affiliated communicationsystem sends to the destination address generator (618) informationregarding the number of signal destinations within it and the number ofentries that each signal destination requires. This information may alsobe stored in RAM (609) such that it may be used by the microprocessor(608) to enter the null information into the destination database (611).The microprocessor (608) monitors the entry of destination data suchthat once it is all entered, the microprocessor (608) can enter the nullinformation.

The second section (1010) of the destination database (611) duplicatesthe information stored in the first section (1009). At start up of thecommunication system network, both sections may simultaneously receiveand store the information. Once the information is stored in bothhalves, one section acts as a sourcing section while the other acts as astoring section. Unlike the signal database, the destination database(611) does not have its sections alternate functions every frame cycle.Instead, the sourcing section of the destination database remains thesourcing section until new information (e.g. volume change, signalsource change, etc.) is received. Once the new information is stored inthe storing section, the sections switch functions. The new informationis then copied into the new storing section which then awaits anotherchange.

The processing circuit (412) of the ambassador board (403), which maycomprise a field programmable gate array, comprises a PCM to linearconverter section (624), a summing section (625), a linear to PCMsection (626), and a diagnostic latch (627). During every frame cycle,the processing circuit (412), under the control of the microprocessor(608), addresses the signal database (616) based on the destinationinformation stored in the destination database (611). The PCM codes areserially read from the signal database (616) are converted to linearsignals by the PCM to linear section (624) and the entries for a signaldestination are summed together by the summer section (625). The summersection (625) continually adds the linear signals together, at thevolume levels indicated, until a 1 is detected in the I/C field. Oncethe 1 is detected, the summer section (625) makes one final summationbefore it outputs a linear resultant to the linear to PCM section (626).The linear resultant is converted into a PCM code by the linear to PCMsection (626) and the resulting PCM code, or processed signals, isrouted to the TDM buffer (620) of the sending encoder (413). Thisprocess is repeated until each of the signal destinations have had aresulting PCM code generated for it.

As previously mentioned, signal destinations comprise AEIs that routesignals to CCMs of a console and BIMs that route signals to a pluralityof communication units. (Also recall that a BIM acts as a signal sourcetoo, such that signals can be transceived to and from the plurality ofcommunication units.) The BIMs may be of two types, the first type isused to interface the communication system to a radio repeater, and thesecond type (smart phone interface (SPI)) is used to interface thecommunication system to telephone lines. The summing of signalsdescribed above, works equally well for summed signals destined for aCCM of a console as well as to either type of BIM. If the BIM is an SPI,the communication units may comprise telephones and/or radio-telephonessuch that several telephones lines may be linked together. For example,if a communication system comprises thirty SPIs each affiliated with atelephone line, all thirty telephone lines could be conferencedtogether. In this example, each SPI would need twenty-nine signalsummations equalling a total of eight hundred and seventy summations,which is well within the capabilities of each ambassador board. Recallthat the best mode contemplates that the destination database (611) willhaving upto 1750 summation entries.

The diagnostic latch (627) of the processing circuit (412) routes eachof the resulting PCM codes to the microprocessor (608) such that thetiming and resultant may be verified. If the microprocessor detects anerror either in the timing or in the resultant, the microprocessor (608)may flag an error and shut the ambassador board down. If redundantambassador boards are used, the error flag would indicate that thebackup ambassador board should be active.

The sending encoder (413) of the ambassador board (403) receives theprocessed signals, or resulting PCM codes via a TDM, or synchronization,buffer (620). The TDM buffer (620), which may comprise a DPRAM havingtwo sections, stores the processed signals in one section during oneframe cycle, then, in the next frame cycle sources the processed signalsto a demultiplexer (621). The demultiplexer (621) routes the processedsignals that are for signal destinations assigned to slots in the firstdestination interface bus to a first encoder (622), and the processedsignals that are for signal destinations assigned to slots in the secondinterface bus to a second encoder (623). The first and second encoders(622 and 623), which may be Manchester encoders, encode the processedsignals and place the encoded processed signals in to the appropriateslots of the destination interface buses (427).

FIG. 7 illustrates a block diagram of an ambassador interface MUXinterface (AIMI) (417) that, as previously mentioned, comprises areceiving circuit (424), a processing circuit (425) and a sendingcircuit (423). The receiving circuit (424) comprises a first framedecoder (717), a second frame decoder (718), a data extractor (719), afirst elastic store (720), a second elastic store (721), a first linedriver (722), and a second line driver (723). The first frame decoder(717), which may be a Manchester decoder, receives and decodes theprocessed signals on the first destination interface bus. The secondframe decoder (718), which may be a Manchester decoder, receives anddecodes the processed signals in the second destination interface bus.The received network data is routed to the data extractor (719), whichmay be a field programmable gate array. The data extractor (719)performs in a similar fashion as the data extractor (603) of theambassador board (403), described above.

The decoded processed signals are routed from the first and second framedecoders (717 and 718) to the first and second elastic stores, orsynchronization buffers (720 and 721), respectively. The first andsecond elastic stores (720 and 721), which may be field programmablegate arrays, function in a similar fashion as the elastic store (604) ofthe received decoder (408) in the ambassador board (403). The sourcesection of the first and second elastic stores are sourcing the decodedprocessed signals to the CEB TDM destination buses (422), via the linedrivers (722 and 723).

The processing circuit (425) comprises a X.25 PC controller (708), a busarbitrator (709), a microprocessor (710), random access memory devices(RAM) (711), an EEPROM (712), an EPROM (716), a data transceiver (713),a dual universal asychronious receiver transmitter (DUART) (714), and awatch dog, or detection circuit, (715). (The DUART (714) is used tointerface the CEB with a CAD, such interfacing is known thus no furtherdiscussion will be given. Also the function of the watchdog circuit isknow such that no further discussion will be given.) The X.25 PCcontroller (708), which may be a device manufactured by Motorola, Inc.receives network data from the data extractor (719) of the receivingcircuit (424) and distributes it throughout the AIMI (417). Network datathat is destined for particular signal sources and/or signaldestinations is routed to a data compressor (701) of the sending circuit(423). The sending circuit (423) will be discussed below.

The bus arbitrator (709), which may be a field programmable gate array,allocates the AIMI data bus (725) among the X.25 PC controller (708),the microprocessor (710), and the data transceiver (713). When the datatransceiver (713), which may be a field programmable gate array, hasaccess to the AIMI data bus (725), it transceives data between the AIMIdata bus (725) and the CEB data bus (420). When the microprocessor (710)has access to the AIMI data bus (725), it controls the routing andstoring of the network data. When the X.25 PC controller (708) hasaccess to the AIMI data bus (725), it receives the network data from thedata extractor (719) and sources it to the rest of the AIMI (417).

The sending circuit (423) of the AIMI (417) prepares the signalsproduced by the signals sources and the data produced by thecommunication system for transmission to the ambassador board. Signalsproduced by the plurality of signal sources are received by a TDM, orsynchronization, buffer (702) which may be a DPRAM. The TDM buffer (702)operates in a similar mode as the TDM buffer (620) of the ambassadorboard. The source section of the TDM buffer (620) routes the signals toa multiplexer (705). The multiplexer (705) combines the signals receivedfrom the TDM buffer (702) with the communication system data receivedfrom the data extractor (701) and with a communication system clock thatis produced by a frame sync generator (703). An address generator (704)produces an addresses and slot assignments for each of the signalsources. The output of the multiplexer (705) is routed to an encoder(706), which may be a Manchester encoder. The encoded signals are placedon the source interface bus (426) via a line driver (707).

The preceding discussion primarily focussed on the conveyance of audiosignals between a plurality of signal sources and signal destinationsthroughout the network under the control of destination data. Thenetwork also conveys network data throughout the network. As previouslymentioned, network data comprises combinations of communication systemdata produced by each of the communication systems. One such type ofcombined communication system data is communication system configurationinformation. As mention previously, communication system configurationinformation includes, but is not limited to, the number of repeaters,number of signal sources, the number of signal destinations, the TDMslot assignments for each signal source and signal destination, the typeof each BIM, and number and codes of communication groups.

Within the communication system network, which presently contemplateshaving upto nine hundred and sixty signal sources, it would beimpractical to store, in each OMI, communication system configurationinformation for each communication system. The best mode contemplatesthat each OMI will store, in existing or additional memory, thecommunication system configuration information of the communicationsystem that the OMI is located in and only specific communication systemconfiguration information of the other communication systems in thenetwork. For example, if an OMI in communication system 1 producessignal destination information that has an AEI, which is affiliated tothe OMI, receiving signals from BIM 1 of communication system 24, theOMI will only store communication system configuration informationpertaining to BIM 1 such as what type of BIM it is and its slot locationwithin communication system 24.

The best mode further contemplates that periodically, or when a newcommunication system is added to the network, that each communicationsystem, via its AIMI board (417), will transmit its communication systemconfiguration information to the other communication systems such thateach communication system may verify that the other communicationsystems have not changed their communication system configurationinformation. However, with present speeds of digital circuitry, it wouldbe impractical to transmit the communication system configurationinformation between all of the communication systems. Thus, within eachAIMI board (417), the communication system configuration information isconverted into a code. The communication system configuration code,which is presently contemplated to be a four bit code, is transmitted toAIMIs of the other communication systems and stored in a communicationsystem configuration code database (not shown), which may be a RAM.

FIG. 12 illustrates a process for maintaining each OMI's database ofcommunication system configuration information and each AIMI'scommunication system configuration code database. At startup, each OMIand AIMI is programmed with relevant communication system configurationinformation and codes, however, such information and codes may changedue to a communication system changing its communication systemconfiguration information and code, a new communication system beingadded to the network, a communication system leaving the network, and acommunication system re-entering the network. At step 1201, eachcommunication system that is operably coupled to the AEB, monitors theAEB data bus for an addition of new communication system to the network.If, during a certain interval (one minute, for example), a newcommunication system is not added to the network (1201), each of thecommunication systems that is connected to the AEB transmits theirsystem configuration code to the AEB data bus (1202). In eachcommunication system, the AIMI compares the stored code of eachcommunication system with the code on the AEB bus (1203). If the AIMIdetects that any of the codes on the AEB data bus is different than itscorresponding stored code (1204), the AIMI stores, in the communicationsystem configuration code database, the code on the AEB bus (1205).

If the codes on the AEB data bus are the same as the ones stored in thecommunication system configuration code database (1204) or after the newcodes are stored (1205), each OMI determines if its specificcommunication system configuration information is up to date (1206). Ifthe specific communication system configuration information is up todate (1206), the process repeats its step (1201). If the specificcommunication system configuration information is not up to date (1206),each OMI that does not have up to date information queries only thecommunication systems that contains the specific information that theOMI stores (1207). Once the OMI receives updated specific information,it stores it (1208) and the process repeats at step 1201.

When a new communication system is added to the network (1201), the newsystem transmits a connection acknowledgement signal to the AEB (1209).After the new communication system receives a confirmation of itsacknowledgement signal, the new communication system and thecommunication systems already connected to the AEB transmit their systemconfiguration code to the AEB bus (1210). The new communication systemand the existing communication systems receive and store the codes foreach of the communication systems, including the new system (1211).After storing the codes, the new communication system transmits itscommunication system configuration information to the existingcommunication systems (1213). Each of the OMIs in the existingcommunication systems stores specific communication system configurationinformation regarding the new communication system (1213), then theprocess proceeds to step 1206 which has been described above.

If a console is equipped with a console interface CPU, or the OMI isequipped with sufficient memory, each OMI may store the communicationsystem configuration information of each communication system in thenetwork. (For a description of a console interface CPU refer toMotorola, Inc. Pub. No. R4-2-73, CENTRACOM Series II Plus ControlCenters (April, 1988).) The process for storing specific communicationsystem configuration information will be used in this embodiment exceptthat when a change is detected in a communication system configurationcode, the OMI will request and store all of the communication systemconfiguration information of the system that produced the change.

Another type of communication system data that is transmitted throughoutthe network is BIM user data, where BIM user data comprises a list,produced by each BIM, of signal sources that have selected the BIM.Depending on the type of BIM, radio interface or telephone interface,the contents of the list will vary. For a telephone interfacing BIM(smart telephone interface (SPI)) the list will comprise entries foreach signal source that has selected the SPI and what type of telephoneconnection was requested. Presently, there are two types of telephoneconnections; private connections and public connections. A privateconnection allocates a telephone line to a requesting signal source andplaces a call to the desired destination, while excluding other signalsources from participating in the call. A public connection allocates atelephone line to a requesting signal source and places the call,however, other signal sources may participate in the call by requestingaccess to the public connection. The requesting process for either typeof telephone connection is known, thus no further discussion will bepresented.

Once a signal source requests that an SPI allocate it a telephone line,the SPI will record, in a line access database (not shown), thecommunication system that the signal source is from, the specific signalsource, and what type of connection was requested. For a publicconnection, the SPI would store the requesting signal source'sinformation, store the type of connection, and designate the requestingsignal source as a primary signal source. When other signal sourcesaccess the public connection, the SPI stores their information andaffiliation with the public connection. In a standalone communicationsystem, the SPI would periodically send a data packet to each of thesignal sources stored in the line access database asking if the line isstill needed. If any of the signal sources responded that the line wasneeded, the SPI would keep the line active.

In the communication system network, it is impractical to have every SPIsend a data packet to each signal source that is accessing it, thus, theSPI periodically sends to the primary signal source, only, a data packetasking the primary signal source if the public line is still needed. Ifthe primary signal source responds that the line is still needed, theSPI keeps the line active. If the primary signal source responds that itdoes not need the line, the SPI will designate a new primary signalsource from the signal sources stored in the line access database anddelete the requesting signal source from the line access database. Oncethe new primary source has been designated, the SPI sends it a datapacket asking it if the public connection is still needed. If theprimary signal source responds that the line is needed, the SPI keepsthe line active, otherwise, the SPI designates another new primarysignal source from the line access database. The line remains activeuntil all the signal sources stored in the line access database aredesignated primary signal source and respond that the line is no longerneeded. It should be noted that more than one signal source may bedesignated as a primary signal source without deviating from the scopeof this feature, nevertheless, the best mode contemplates that only onesignal source will be designated as a primary signal source at a time.

A BIM that is operating as a radio interface in a standalonecommunication system would store each signal source that was accessingit and query each signal source whether the BIM was still needed forthat signal source. However, in a communication system network thiswould be impractical. Instead, the best mode contemplates that each BIMwill store upto three signal sources that are accessing it in an accessdatabase (not shown). When a BIM enters, or re-enters, a communicationsystem of the network, it transmits a data packet to all of the signalsources in the network, where the data packet asks each signal source ifit has the BIM selected. The first three signal sources to respond tothe data packet will be stored in the access database. Of the signalsources stored, one of them is designated as a primary signal source,where the primary signal source refreshes the BIM. The primary signalsource will periodically send to the BIM a data packet indicating thatit is still selected. When the primary signal source deselects the BIM,it sends a data packet to the BIM indicating that it has deselected theBIM. Upon receiving the deselection data packet, the BIM designates anew primary signal source from the signal sources stored in the accessdatabase. If no signal sources are stored in the access database, theBIM transmits a data packet to the network that asks if any signalsources have selected the BIM. A BIM may store more or less than threesignal sources that have selected it, nevertheless, the best modecontemplates that a BIM will store three signal sources.

Another type of communication system data is BIM status data, whichindicates the status of a BIM in a communication system such as, forexample, select status, auxiliary input/outputs, and link status. EachAIMI of a communication system comprises a BIM status database (notshown) that contains the status of each BIM in the communication system.Approximately every five seconds, each BIM transmits its status to theAIMI. If the AIMI detects that a BIM's status has changed, the AIMIstores the change, flags the change, and transmits the change to thenetwork. The AIMI also transmits the status of BIMs that did not changetheir status to the network at varying intervals.

The varying time intervals at which the AIMI transmits non-changed BIMstatus is determined by the number of BIMs that did not change itsstatus during a predetermined time period and by a selected number BIMstatuses that an AIMI may transmit at one time. The best modecontemplates that the status of every BIM will be transmitted to thenetwork every minute and that an AIMI may transmit the status of fourBIMs at any given time. Thus, if a communication system comprises xnumber of BIMs and none of the BIMs have changed its status, the AIMIwill transmit the status of four BIMs every 4*60/x seconds. If n numberof BIMs change their status, the AIMI will transmit the status ofnon-changing BIMs every 4*60/(X-n) seconds. For example, if thecommunication system has 20 BIMs and none of them have changed theirstatus, the AIMI will transmit the status of the first four BIMs storedin the BIM status database every 12 seconds (4*60/20). If, during thenext varying time interval, five BIMs change their status, the next fournon-changing BIM status will be sent 16 seconds (4*60/(20-5)) after theprevious status update information was sent.

With each communication system, via its affiliated ambassador board,transmitting and receiving network data as described above, access tothe AEB data bus (405) must be controlled. The system synchronizationcircuit (404) polls, in a round robin fashion based on an ambassadorboard's physical location in the card cage, each ambassadors board (403)as to whether it wants access to the AEB data bus (405). When anambassador board (403) indicates that it wants the AEB data but (405),the system synchronization circuit (404) stops polling until therequesting ambassador board is done with the AEB data bus (405). Whenthe requesting ambassador board is done with the AEB data bus (405), thesystem synchronization circuit (404) resumes the polling process withthe next ambassador board (403) in the queue. When network data is notbeing transmitted on the AEB data bus (405), the system synchronizationcircuit (404) transmits a bus idle signal. Also, when an ambassadorboard is not transmitting data, the second X.25 PC controller (612) isproducing a pad signal which is prevented from being placed on the AEBdata bus (405) by the data arbiter (613).

FIG. 13 illustrates a logic diagram for accessing the AEB data bus (405)by an ambassador board (403). At step 1301 an ambassador board (403)requests access to the AEB data bus (405). The ambassador board (403)will request the AEB data bus as soon as it has data to transmit on thebus (405), however, it will not get access to the bus (405) until it ispolled by the system synchronization circuit (404) (1302). Once theambassador board is granted access to the bus (1302), the microprocessor(608) of the requesting ambassador board places the line driver (624) inan active state such that the pad signals being generated by the secondX.25 PC controller (612) placed on the AEB data bus (405). Typically,each of the second X.25 PC controllers (612) continually produces padsignals except for when it is transmitting data onto the AEB data bus(405). The pad signals are prevented from being placed on the AEB databus because the line driver (624) is normally in a high impedance state.

The pad signals on the bus indicates to all of the ambassador boards,including the requesting ambassador board, that data is going to betransmitted on the bus. Once the microprocessor (608) of the requestingambassador board recognizes the pad signals, it enables the second X.25PC controller (612) to transmit the data onto the AEB data bus (1303).After the data has been transmitted on the bus (405), the second X.25 PCcontroller (612) resumes transmitting pad signals. If the microprocessor(608) of the requesting ambassador board received the first set of padsignals, the data, and the second set of pad signals (1304), themicroprocessor (608) places the line driver (624) in a high impedancestate such the pad signals are no longer placed on the bus (405). Oncethe liner driver is placed in a high impedance state, the systemsynchronization circuit (404) resumes placing the idle signals on thebus which indicates the end of the data transmission (1305).

If the microprocessor (608) of the requesting ambassador board does notreceive either the first set of pad signals, the data, or the second setof pad signals, is the microprocessor (608) receiving idle signals(1306). If the microprocessor (608) is receiving idle signals (1306),the ambassador board re-requests access to the AEB data bus (405)(1301). If the microprocessor is not receiving idle signals (1306), thecommunication system network is shutdown such that a system diagnosticscheck can be performed.

What is claimed is:
 1. In a communication system network that includes aplurality of communication systems and a processing multiplexer, whereineach of the plurality of communication systems includes a processingmultiplexer interface means for interfacing with the processingmultiplexer, a plurality of signal sources, and a plurality ofdestinations, wherein the processing multiplexer includes system datadatabase means for storing information pertaining to communicationsystem configuration data, and wherein the system data database meanshas a predetermined number of entries, a method for entering theinformation pertaining to the system configuration data into the systemdata database means, the method comprises the steps of:a) querying theprocessing multiplexer interface means of at least one of the pluralityof communication systems for the information pertaining to thecommunication system configuration data of the at least one of theplurality of communication systems; b) receiving the informationpertaining to the communication system configuration data from theprocessing multiplexer interface means; c) querying the processingmultiplexer interface means of the at least one of the plurality ofcommunication systems for number of entries in the system data databasemeans that are required for the at least one of the plurality ofcommunication systems to produce a requested number of entries; d) whenthe system data database means has at least the requested number ofentries available, allocating the requested number of entries in thesystem data database means for the information pertaining to thecommunication system configuration data of the at least one of theplurality of communication systems to produce allocated entries; and e)entering the information pertaining to the communication systemconfiguration data into the allocated entries.
 2. The method of claim 1further comprises updating the system data database means with newinformation pertaining to communication system configuration data of aparticular signal destination of the at least some of the plurality ofsignal destinations when the communication system configuration data ofthe particular signal destination changes.
 3. The method of claim 1further comprises verifying that the information pertaining to thecommunication system configuration data of each of the at least some ofthe plurality of signal destinations entered into the allocated entriesof the system data database means is the information pertaining to thecommunication system configuration data of each of the at least some ofthe plurality of signal destinations received.
 4. The method of claim 3further comprises requerying the processing multiplexer interface meanswhen the information pertaining to the communication systemconfiguration data of each of the at least some of the plurality ofsignal destinations entered into the allocated entries of the systemdata database means does not substantially match the informationpertaining to the communication system configuration data of each of theat least some of the plurality of signal destinations received.
 5. In acommunication system network that includes a plurality of communicationsystems and a processing multiplexer, wherein each of the plurality ofcommunication systems includes a processing multiplexer interface and aplurality of signal destinations, wherein the processing multiplexerincludes a plurality of communication system interfaces, wherein eachcommunication system interface includes a destination database whereineach of the plurality of communication systems is operably coupled to atleast two communication system interfaces, and wherein each of thedestination databases has as predetermined number of entries, a methodfor entering information pertaining to communication systemconfiguration data into a destination database, the method comprises thesteps of:a) querying, by an active communication system interface, theprocessing multiplexer interface of a communication system that theactive communication system interface is operably coupled to for theinformation pertaining to the communication system configuration data ofthe communication system; b) receiving the information pertaining to thecommunication system configuration data from the processing multiplexerinterface to produce received information; c) querying the processingmultiplexer interface of the communication system for number of entriesin the destination database that are required for the receivedinformation to produce a requested number of entries; d) when thedestination database of the active communication system interface andwhen the destination database of the active communication systeminterface and when the destination database of a backup communicationsystem interface that is operably coupled to the communication systemeach have at least the requested number of entries available, allocatingentries in the destination database of the active communication systeminterface and entries in the destination database of the backupcommunication system interface for for the communication systemconfiguration data of the communication system to produce allocatedentries; storing the received information into the allocated entries ofthe destination database of the active communication system interfaceand of the destination database of the backup communication systeminterface f) comparing the received information stored in thedestination database of the active communication system interface withthe received information stored in the destination database of thebackup communication system interface; and g) when the receivedinformation stored in the destination database of the activecommunication system interface does not substantially match the receivedinformation stored in the destination database of the backupcommunication system interface, requerying, by the active communicationsystem interface, the processing multiplexer interface of thecommunication system for the information pertaining to the communicationsystem configuration data of the communication system.
 6. The method ofclaim 5 further comprises updating the destination database with newinformation pertaining to communication system configuration data of aparticular signal destination when the communication systemconfiguration data of the particular signal destination changes.